Apparatuses and methods of the aforementioned type are known in the art. For instance, patent application DE 10 2004 046 038 A1 discloses a virtual operating room simulator, which is intended in particular for training in endourological interventions. Contrary to surgical or endoscopic training models which make use of an actual reconstruction of a body part or of an internal body cavity, into which the point of an endoscope is inserted, to simulate a surgical or minimally invasive procedure, with a virtual simulator using “virtual reality” methods and computer support an image of a virtual environment, in particular of a body cavity, is generated interactively with user influence. According to DE 10 2004 046 038 A1, the virtual operating room simulator includes a simulation digital unit to generate such a virtual endoscopic image in real time, an instrument whose proximal part (that is, closer to the user) is copied from that of an endoscopically insertable instrument, and an instrument input unit to record the instrument. In addition to the display of the virtual image, the force reaction on the instrument or on a resection loop positioned distally (that is, remote from the user) is computed and communicated to the user. The instrument that is to be inserted into the instrument input unit and copied from a resectoscope comprises a feeder line and a run-off line for flushing liquid. Stopcocks are provided in each of the lines to allow opening and closing of the lines. Associated with these stopcocks are micropotentiometers that help to record the movement of the stopcocks. The corresponding signals are transmitted to the simulation processor unit and evaluated there to compute the virtual image.
Disclosed in US 2005/0196739 A1 is an endoscopic simulation system that includes a training endoscope especially adapted for simulation as well as a detector that records the movements of the distal end of a flexible shaft of the training endoscope controlled by the user, an image recording apparatus that registers the shape of a patient's internal hollow organ, and an image processor that generates a virtual three-dimensional image of the hollow organ from the recorded data. The operating portion of the training endoscope provides pushbuttons for air or for water flushing as well as for siphoning. On actuation of the particular pushbuttons, their movements are recorded and conveyed to the processor via an electric line.
Recording the movement of the stopcocks for air, water, and or siphoning and conversion into signals that can be evaluated by the image processor requires the integration of electronic or electrical elements into the training endoscope. With a flexible endoscope the actuation elements for air, water and siphoning are usually located in the handle. However, practically no space is available there for the related mechanical and electronic components. It must be kept in mind here that for a realistic simulation the handle of the training endoscope should correspond as closely as possible to that of the original endoscope in terms of size, shape and weight. Therefore it is very complex structurally to integrate appropriate sensors into the handle of the training endoscope. This is even more the case when an original endoscope appropriate for surgical procedures is to be adapted for use in such a simulator.
To ensure training conditions that are as realistic as possible, it is also essential to bear in mind, when using a training endoscope or a corresponding conversion of an original endoscope, that for the user the changes from the endoscope used clinically should be as few as possible in terms of the type and effect of the valve actuation, the force to be exerted for this, and the palpable reaction of the valve pushbuttons. Even this cannot be achieved to the desired extent, or is possible only at great effort, when sensors are to be integrated into the training endoscope to record the movement of the valve pushbuttons.
With many endoscopes, in particular flexible endoscopes, for controlling the three functions of siphoning, insufflating and flushing there are only two valve pushbuttons available to act on the corresponding lines, which run from a proximally mounted connection to the corresponding pumps through the handle all the way to the distal end section of the endoscope. By depressing a first valve pushbutton, a first valve is actuated that acts on the siphoning line by producing, or completely or partially interrupting, a connection between a siphoning pump that is connected to a proximal part of the siphoning line and a distal part of the siphoning line positioned distally from the valve. Accordingly, by depressing a second valve pushbutton a second valve is actuated that produces, or completely or partially interrupts, a connection between a flushing liquid reservoir, which is impacted with pressure by a flushing pump and is connected to a proximal part of the flushing line, and a distal part of the flushing line mounted distally from the valve. The second valve also comprises an aperture that is connected with the proximal and distal parts of the insufflation line. Connected with the proximal part of the insufflation line is an insufflation pump that produces an insufflation gas, such as air, at an appropriate excess pressure. As long as the aperture is open the insufflation gas can escape through the aperture so that no substantially increased pressure can build up in the insufflation line. In order to introduce gas via the distal part of the insufflation line into a body cavity into which the distal end of the endoscope is inserted, the user closes the aperture with one finger. Now pressure can build up in the insufflation line and the gas delivered by the insufflation pump is conveyed into the distal part of the insufflation line and from there into the body cavity. By simultaneously closing the aperture and partially depressing the second valve pushbutton, it is possible to insufflate and flush at the same time. In this manner the three functions, siphoning, insufflating and flushing, can be controlled with the help of two valve pushbuttons.
For a realistic simulation, the depressing of the valve pushbuttons must be detected and evaluated, as must the closing of the aperture in the second valve pushbutton. While the movement of the valve pushbuttons can be detected on depressing, for example by switches or potentiometers, recognition of the closing of the aperture requires a sensor that detects the presence of the finger that is closing the aperture. For this purpose it is possible in theory to employ a reflecting light barrier, but in this manner it is not possible to distinguish a complete closing of the aperture from an incomplete closing. Realistic training in operating the valves is therefore scarcely possible in the described arrangement of valves.